Nick Diaz and his camp have stepped up their campaign to force a rematch with Georges St-Pierre, after releasing text message conversations that they claim are evidence of a weigh-in cover-up.

Diaz is angling for a second meeting with UFC welterweight champion St-Pierre, following suggestions that the Canadian did not make the official weight for their meeting in Montreal at UFC 158.

In a Diaz-camp recorded video posted on YouTube - one that was subsequently pulled down - UFC executive Michael Mersch was shown telling Diaz moments before the weigh-in that "in an off-the-record type thing" the Quebec commission "don't count the decimal" in weigh-ins, meaning 170.9 pounds would could as 170lb - the welterweight limit.

Fighters in the UFC are typically allowed to weigh up to one pound over the legal limit at weigh-ins, but championship bouts dictate that the two rivals must hit the precise number. Diaz's camp suggests that the rules were bent in order to accommodate Canadian hero St-Pierre's difficulty in making weight.

The Quebec commission does not have a record of employing such a policy - announcing decimals in the past, and even forcing Bernard Hopkins to cut 0.9lbs in similar circumstances for a meeting with Jean Pascal - but later confirmed that was the case, in conjunction with the UFC.

After asking Mersh to elaborate on his comments made prior to the weigh-in, those caught on camera, the UFC official stonewalled Tweedale hours later.

"I have no idea what you are talking about," Mersh said, in texts seen by Bloody Elbow.

He added: "The Commission determined both fighters weighed 170 or less. What am I supposed to do about that? I would think Nick would be excited to compete for the UFC welterweight title. Seems like he's focused on the wrong issue."

Hamelin offered a similar version, replying to questions about ignoring the decimal by saying: "The [sic] were no specials rules!"

The Canadian then added: "Jonathan, if you need a [sic] official answer, send a [sic] official email."

Hours later, the Quebec commission released a statement saying "our regulation does not take decimals into account", and that those regulations "have been in place for several years" - despite evidence to the contrary.

While unwilling to suggest whether the blame lies with the UFC or some mistakes on the part of the Quebec commission, Tweedale believes the incident means Diaz is within his rights to demand a rematch.

"We appreciate that Mr Mersch was in a difficult position, evidently having been instructed by the Quebec commission to relay to Mr Diaz some last-minute, unlawful 'rule changes' to give the hometown fighter a reprieve from his duty to make weight at 170 pounds," Tweedale said. "But the transcript shows Mr. Mersch's views on the matter.

"If he and the UFC thought that this last-minute rule change was above-board, lawful, or defensible, Mersch presumably would have answered our legitimate questions about the 0.9 and ignoring the decimal in a forthright and straightforward manner."

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